Seymour is a paternal great-grandfather of Sheldon J. Plankton, the father-in-law of Grand Dad Plankton, the maternal grandfather of Gordon Plankton and Silas Plankton, the grandfather-in-law of Mama Plankton, and also the great-grandfather-in-law of Karen Plankton. He appears in the comic A Plankton Family Tree.
He is an old plankton with four curled arms and legs, two buck teeth, and a pipe in his mouth.
At some point, he married Basia. Later, they were run out of their hometown for evil scheming and had to move to Bikini Bottom. Here, they had Alvin, Moe Bros and Lily Plankton. His last name, which is also Lily’s maiden name, has never been revealed.
Role in comic
He is a representation of Plankton's family tree.
|Plankton (V • E)|
Sheldon J. Plankton • Clem • Rufus • Rainchild • Sheldon J. Plankton (Mr. Plankton's Universe) • Gordon Plankton • Lily Plankton • Basia • Alvin • Silas Plankton • Planktonamor • Dead Eye Plankton • Grand Dad Plankton • Green PlanKrab • Ideal Plankton • Cousin Marvin • Dream Lily Plankton • Mama Plankton • Moe Bros • PlanKrab • Plankton zombies • Planktonamor • Red PlanKrab • Seymour • Sheldon J. Plankton (Bikini Bottom 2)